Question

What are the oxidation states of Fe and Ti in the ore ilmenite \(\left(\mathrm{FeTiO}_{3}\right)\) ?

Short answer

Fe is +2 and Ti is +4 in ilmenite.

Step-by-step solution

Identify the Components

Firstly, recognize that ilmenite is made up of Fe, Ti, and O atoms. Oxygen almost always has an oxidation state of -2.

Determine Oxygen's Contribution

Since there are three oxygen atoms, their total contribution to the charge is \(3 \times (-2) = -6\).

Set Up the Charge Balance Equation

Ilmenite is a neutral compound, so the total oxidation states must cancel out to zero. Let the oxidation state of Fe be \(x\) and that of Ti be \(y\). The equation becomes \(x + y + (-6) = 0\).

Utilize Common Oxidation States

Iron, in such compounds, typically takes an oxidation state of +2. Thus, assume \(x = +2\).

Solve for Titanium's Oxidation State

Substituting \(x = +2\) in the equation, we have \(2 + y - 6 = 0\) which simplifies to \(y = +4\). So, the oxidation state of Ti is +4.

Key concepts

Ilmenite

Ilmenite is a naturally occurring ore that features prominently in geology and mineralogy. It has the chemical composition of \( \text{FeTiO}_3 \), which signifies that each molecule of ilmenite consists of one iron (Fe) atom, one titanium (Ti) atom, and three oxygen (O) atoms. This mineral is an iron-titanium oxide, and certain characteristics make it invaluable, such as being a source of titanium dioxide used in various industries—including pigments, coatings, and plastics. Its crystal structure typically presents as black or dark brown, often found in igneous and metamorphic rocks. Understanding its chemical composition helps in identifying the roles each element plays in the compound, especially when determining oxidation states.

Charge Balance

Charge balance is a key concept in determining the oxidation states of elements within a compound. This concept asserts that for a compound to remain neutral, the total positive and negative charges must sum up to zero. In the case of ilmenite \( \left( \mathrm{FeTiO}_{3} \right) \), oxidation states of iron \( (\text{Fe}) \), titanium \( (\text{Ti}) \), and oxygen \( (\text{O}) \) must balance out. Oxygen typically has an oxidation state of \(-2\). Since there are three oxygen atoms in ilmenite, their combined charge is \(3 \times (-2) = -6\). The role of charge balance is to ensure that when these charges are added to those of Fe and Ti, the total is zero, preserving the neutrality of the compound.

Neutral Compound

A neutral compound is one in which the sum of all oxidation states of the constituent atoms equals zero. This ensures that there is no overall electrical charge on the compound. In ilmenite, we apply this principle by equating the total oxidation charge to zero: - The three oxygen atoms contribute \(-6\) to the charge. - Assuming typical oxidation states for iron, \(\text{Fe}^{+2}\), and solving for titanium, we set up the equation \(2 + y - 6 = 0\) where \(y\) is the oxidation state of titanium.The balancing of these charges is crucial to confirming that a compound is indeed neutral and stable.

Titanium Oxidation State

The oxidation state of titanium in ilmenite can be determined through understanding charge balance and typical oxidation states of other atoms within the compound. In this mineral context, ilmenite provides a classic case of oxidation state derivation where known values assist in discovering unknowns. Once assuming iron \(\text{Fe}\) has an oxidation state of \(+2\), we solve the charge balance equation: - \(x + y + (-6) = 0\)- Substitute \(x = +2\), leading to \(2 + y - 6 = 0\)From this equation, \(y\) is solved to be \(+4\), establishing that titanium in ilmenite has an oxidation state of \(+4\). This state indicates titanium loses four electrons, contributing to the charge balance within the compound.